Truvada (tenofovir and emtricitabine)

Newly licensed for preventing HIV in the sexual partners of people who are HIV positive, we explain everything you need to know if you or your partner have been prescribed this antiretroviral to treat or prevent HIV infection

10/07/2017

What is Truvada used for?

Treating HIV infection. Truvada must be used in combination with other anti-HIV medicines to treat HIV, because the virus can become resistant to one agent very quickly. This is known as combined antiretroviral therapy (cART) or highly active antiretroviral therapy (HAART). Truvada is used in conjunction with other anti-HIV drugs that attack the HIV virus in different ways. This helps prevent the virus becoming resistant to the medicines.

Truvada can also be prescribed to people who don't have HIV, to reduce the risk of catching HIV if their sexual partner is HIV positive. This is known as pre-exposure prophylaxis or PrEP.

How does Truvada work?

Truvada tablets contain two active ingredients, tenofovir and emtricitabine. Emtricitabine belongs to a class of medicines called nucleoside reverse transcriptase inhibitors (NRTIs). Tenofovir is a very closely related medicine, called a nucleotide reverse transcriptase inhibitor. Both medicines are used in the treatment of HIV (human immunodeficiency virus) infection.

AIDS (acquired immune deficiency syndrome) is caused by infection with HIV. This virus invades cells of the immune system, particularly the white blood cells known as CD4 T-helper lymphocytes. These cells normally work to activate other cells in the immune system to fight infection. Since HIV kills CD4 T-helper cells, over time the body becomes less able to fight the virus or subsequent infections.

Once the virus is inside the CD4 T-cell it multiplies. Part of the process of viral multiplication involves the conversion of the virus genetic material, RNA, into DNA. This is achieved by a viral enzyme called reverse transcriptase. Emtricitabine and tenofovir both work by blocking the action of this enzyme. Each medicine blocks the enzyme in a slightly different way. Blocking the action of the enzyme interferes with the conversion of viral RNA into DNA, which stops the virus from multiplying.

There is no cure for HIV, but emtricitabine and tenofovir are among several medicines that lower the amount of virus in the body (viral load), help the immune system to recover, and therefore slow down or stop the progression of the disease from HIV to AIDS.

How do I take Truvada?

To treat and prevent HIV the usual dose is one Truvada tablet taken once a day, although if you have kidney problems your doctor may ask you to take the medicine less frequently than this. Always follow the instructions given by your doctor. These will also be printed on the dispensing label that your pharmacist has put on the packet of medicine.

Truvada tablets should be taken with food, as this increases the absorption of the medicine into the body.

The tablet should be swallowed with a drink of water. However, if you have problems swallowing the tablet, it can be dispersed in 100ml of water, orange juice or grape juice before taking.

Your Truvada tablet should be taken at the same time each day. If you forget to take a dose you can take it with food up to 12 hours late. However, if you are more than 12 hours late taking a dose you should not take the missed dose; just take your next dose at your usual time. Do not take a double dose to make up for a missed dose.

If you vomit within one hour of taking a tablet you should take another tablet with food. If you vomit more than one hour after taking a tablet you don't need to take another tablet; just take your next dose as usual when it is due.

You must keep taking this medicine regularly every day unless your doctor tells you to stop.

What should I know about taking Truvada?

The HIV virus is very good at becoming resistant to anti-HIV medicines. For this reason it is very important that you carefully follow your doctor's instructions for taking your anti-HIV medicines, in order to maintain effective levels of the medicines in your blood. If the blood levels of the medicines drop, the virus will be given more chance to replicate and develop resistance to the drugs. Skipping even a few doses increases the risk of treatment failure, so you should make sure that you take all your doses at the correct time, and that you visit your doctor for repeat prescriptions before you run out.

If you're taking Truvada alongside other medicines to treat HIV this has been shown to reduce the risk of transmitting the virus to other people through sexual contact. However, it does not remove this risk entirely. You should continue to use condoms to avoid transmitting the virus to your sexual partner, even if they are also taking Truvada to help prevent HIV infection.

If you're taking Truvada to help prevent HIV it's important that you're aware that it may not stop you getting HIV. You still need to practice safe sex, use condoms, not share items that have blood or body fluids on them, and get regularly tested for STIs, since some STIs can increase your risk of catching HIV.

People taking antiretroviral medicines may gain weight and may also experience increases in the levels of sugar and fats in their blood. However these changes are in part linked to the improvement in control over your HIV and your lifestyle. Your doctor may want to monitor the levels of lipids (eg cholesterol) and sugar (glucose) in your blood, and may prescribe additional medicines for any lipid disorders that occur during your treatment.

Some people being treated with combination antiretroviral therapy may develop a bone condition called osteonecrosis. The risk of the condition is thought to be increased by corticosteroid use, alcohol consumption, severe immunosuppression, higher body mass index, advanced HIV disease and long-term use of antiretroviral medicines. If you notice any joint stiffness, aches and pains (especially of the hip, knee and shoulder) or difficulty in movement while taking antiretrovirals, you should tell your doctor so this can be investigated.

If you have advanced HIV and a history of opportunistic infections such as pneumocystis carinii pneumonia (PCP) or cytomegalovirus (CMV), you may experience signs and symptoms of inflammation from previous infections soon after you start combination anti-HIV treatment. It is believed that these symptoms are due to an improvement in the body's immune response, which enables the body to fight infections that may have been present with no obvious symptoms. You should tell your doctor immediately if you get any signs or symptoms of infection, such as inflammation or high temperature.

Who might need a lower Truvada dose or extra monitoring?

People over 65 years of age.

People with decreased kidney function or a history or risk of kidney problems. Your kidney function should be monitored.

People with liver disease, particularly hepatitis B or C. Your liver function should be monitored.

Who should not take Truvada?

People who are allergic to any ingredient of the medicine. Check the ingredients listed in the leaflet that comes with the medicine if you know you have specific allergies.

Truvada is not recommended for children under 12 years of age, or for children under 18 years of age with kidney problems.

Truvada is not recommended for people with severely reduced kidney function or those needing dialysis.

Can I take Truvada while pregnant or breastfeeding?

The safety of Truvada for use during pregnancy has not been fully established. However, combined antiretroviral therapy is widely used to help prevent HIV infection passing from a pregnant woman to her developing baby. This should only be prescribed by specialists in HIV infection and it's important to get medical advice from your doctor straight away if you think you could be pregnant while you are taking Truvada.

In the UK it's currently recommended that women infected with HIV should not breastfeed their infants, regardless of their treatment, in order to avoid transmitting the virus to the baby in the breast milk. Mothers are advised to feed their babies with formula from birth. You should discuss this with your doctor.

What are the possible side effects of Truvada?

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with Truvada. Just because a side effect is stated here does not mean that all people using this medicine will experience that or any side effect.

Rare (affect between 1 in 1000 and 1 in 10,000 people)

Kidney problems, including kidney failure and kidney inflammation. Your kidney function should be monitored before starting and regularly throughout treatment with Truvada.

Softening of the bones (osteomalacia) that may result in fractures (tell your doctor if you notice any bone pain while you are taking this medicine).

Read the leaflet provided with the medicine, or talk to your doctor, nurse or pharmacist if you want any more information about the possible side effects of Truvada. If you think you have experienced a side effect, did you know you can report this using the yellow card website?

Can I take other medicines with Truvada?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with Truvada. Similarly, check with your doctor or pharmacist before taking any new medicines with Truvada, to make sure that the combination is safe.

Truvada should not be taken in combination with lamivudine or other medicines that contain emtricitabine or tenofovir.

There may be an increased risk of kidney problems if tenofovir is taken in combination with other medicines that are known to have side effects on the kidneys, such as those listed below, or by people who have recently taken one of these medicines. These medicines should not be taken by people taking tenofovir unless combined use is unavoidable, in which case your kidney function should be monitored every week:

adefovir (this should not be used with Truvada)

aminoglycoside antibiotics, eg gentamicin, neomycin

amphotericin B

cidofovir

foscarnet

ganciclovir

interleukin-2

pentamidine

tacrolimus

vancomycin.

You should not take non-steroidal anti-inflammatory drugs (NSAIDs - painkillers such as ibuprofen, diclofenac or naproxen) while you are taking Truvada, unless these have been prescribed by your doctor, because your kidneys may need extra monitoring.

There may also be an increased risk of side effects on the kidneys if tenofovir is used in combination with protease inhibitors boosted with ritonavir or cobicistat.

Emtricitabine and tenofovir are removed from the body by the kidneys. The manufacturer of Truvada states that it should be used with caution in combination with medicines that are known to affect kidney function, or that are also eliminated from the body by the kidneys, because the safety of such combinations have not yet been evaluated. Your doctor or pharmacist will check the combination of medicines you are taking and perform extra monitoring if considered necessary.

The weight loss medicine orlistat has been reported to reduce the absorption of anti-HIV medicines from the gut and could make them less effective.

Tenofovir may increase the blood level of didanosine and hence may increase the risk of its side effects. Studies using lower doses of didanosine to avoid this problem have shown a high rate of early virological failure and emergence of resistance. For this reason, using Truvada in combination with didanosine is not recommended.

There may be a risk of treatment failure or the emergence of viral resistance at an early stage if Truvada is used in combination with another nucleoside reverse transcriptase inhibitor, eg abacavir, stavudine, zidovudine. If you are taking any of these medicines with Truvada your doctor will monitor you regularly.

Other medicines containing the same active ingredients

There are no other medicines available in the UK that contain both emtricitabine and tenofovir as the active ingredients.

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